/* This file is based on the GLIB utf8 validation functions. The

 * original license text follows. */

/* gutf8.c - Operations on UTF-8 strings.

 *

 * Copyright (C) 1999 Tom Tromey

 * Copyright (C) 2000 Red Hat, Inc.

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 02111-1307, USA.

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include <stdlib.h>

#include "utf8.h"

#define UNICODE_VALID(Char)                   \

    ((Char) < 0x110000 &&                     \

     (((Char) & 0xFFFFF800) != 0xD800) &&     \

     ((Char) < 0xFDD0 || (Char) > 0xFDEF) &&  \

     ((Char) & 0xFFFE) != 0xFFFE)

#define CONTINUATION_CHAR                           \

 do {                                     \

  if ((*(const unsigned char *)p & 0xc0) != 0x80) /* 10xxxxxx */ \

    goto error;                                     \

  val <<= 6;                                        \

  val |= (*(const unsigned char *)p) & 0x3f;                     \

 } while(0)

const char *

avahi_utf8_valid (const char *str)

{

  unsigned val = 0;

  unsigned min = 0;

  const char *p;

  for (p = str; *p; p++)

    {

      if (*(const unsigned char *)p < 128)

  /* done */;

      else

  {

    if ((*(const unsigned char *)p & 0xe0) == 0xc0) /* 110xxxxx */

      {

        if ( ((*(const unsigned char *)p & 0x1e) == 0))

    goto error;

        p++;

        if ( ((*(const unsigned char *)p & 0xc0) != 0x80)) /* 10xxxxxx */

    goto error;

      }

    else

      {

        if ((*(const unsigned char *)p & 0xf0) == 0xe0) /* 1110xxxx */

    {

      min = (1 << 11);

      val = *(const unsigned char *)p & 0x0f;

      goto TWO_REMAINING;

    }

        else if ((*(const unsigned char *)p & 0xf8) == 0xf0) /* 11110xxx */

    {

      min = (1 << 16);

      val = *(const unsigned char *)p & 0x07;

    }

        else

    goto error;

        p++;

        CONTINUATION_CHAR;

      TWO_REMAINING:

        p++;

        CONTINUATION_CHAR;

        p++;

        CONTINUATION_CHAR;

        if ( (val < min))

    goto error;

        if ( (!UNICODE_VALID(val)))

    goto error;

      }

    continue;

  error:

    return NULL;

  }

    }

  return str;

}